[herrhansen]

Hi.

I am looking for someone having experiences with the delepine reaction? I wanted to make a primary amine from my primary alkylbromide, but couldnt find any references. So I just reacted the alkylbromide in anhydrous EtOH with two eq. hexamine - allowed it to stir for 25 mins, heated it a little and added formic acid and refluxed for 4 hours. It gave me a new spot on TLC, which I will have to identify on NMR. As the first step is an SN2 it could probably be better to use more than two eq. of the hexamine to increase the rate. I have also seen the reaction done in ethanolic HCl.

I could do the SN2 with ammonia, but I would like to try out the delepine reaction instead, so any references or experiences would be greatly appreciated.

Thanks.

[Dan]

You could also displace bromide with azide and then reduce by one of the several methods of azide reduction.

[AWK]

Did you search internet for this reaction.
Google gives you the starting point immediately
http://www.organic-chemistry.org/namedreactions/delepine-reaction.shtm

[Åke]

Hi.

I am looking for someone having experiences with the delepine reaction? I wanted to make a primary amine from my primary alkylbromide, but couldnt find any references. So I just reacted the alkylbromide in anhydrous EtOH with two eq. hexamine - allowed it to stir for 25 mins, heated it a little and added formic acid and refluxed for 4 hours. It gave me a new spot on TLC, which I will have to identify on NMR. As the first step is an SN2 it could probably be better to use more than two eq. of the hexamine to increase the rate. I have also seen the reaction done in ethanolic HCl.

I could do the SN2 with ammonia, but I would like to try out the delepine reaction instead, so any references or experiences would be greatly appreciated.

Thanks.

There is a reliable, large-scale Organic Syntheses method: http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv5p0121

Gabriel or Fukuyama amine synthesis might be alternatives to consider, as well as S_N2 with NaN₃ (rather than ammonia) followed by catalytic hydrogenation of alkyl azide. The choice of method ultimately depends on the functional groups present on your substrate and you haven't told us what they are.